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Carhartt Base Force Lightweight Bottoms Review

A warmer lightweight option that has a lot of potential to improve upon design
Carhartt Base Force Lightweight Bottoms
Photo: Amazon
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Price:  $25 List | $29.45 at Amazon
Pros:  Affordable, lightweight, warm for weight
Cons:  Instant fabric tear, baggy fit, sticky exterior gridded fleece
Manufacturer:   Carhartt
By Aaron Rice ⋅ Review Editor  ⋅  Nov 12, 2020
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61
OVERALL
SCORE


RANKED
#9 of 9
  • Warmth - 30% 6
  • Breathability - 30% 7
  • Comfort and Fit - 30% 5
  • Durability - 10% 7

Our Verdict

For those seeking a lightweight bottom that actually favors warmth over breathability, the Carhartt Base Force Lightweight bottoms might be your match. This slightly baggy, synthetic base layer earns extra warmth points by incorporating a mini-gridded fleece design that helps trap warm air closer to your skin. While we believe that this design would be much more effective next-to-skin on the inside of the pant, we were still quite impressed by the Base Force Lightweight's warmth-to-weight ratio. For those who run a bit colder or are looking to add a layer to their workwear for a low price, these base layer bottoms fit the bill. We find these better suited for daily wear warmth rather than outdoor performance apparel.

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$29.45 at Amazon
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Overall Score Sort Icon
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Star Rating
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Pros Affordable, lightweight, warm for weightSoft next-to-skin, super warm for its weight, durable and all-naturalBreathable, highly efficient wicking, comfortable merino/recycled polyester blend, impressively durable100% recycled polyester, light fabric weight, impressive loft and warmthUnbeatable price, breathable, quick drying, functional
Cons Instant fabric tear, baggy fit, sticky exterior gridded fleeceA touch heavy for fabric weight, slow to dry after washingNot designed for mid-winter warmth, relatively heavy for fabric weight, thin waist bandQuestionable durability, saggy bottomShort cut legs, average comfort and warmth
Bottom Line A warmer lightweight option that has a lot of potential to improve upon designUndeniably comfortable, warm, and breathable, this rough-and-tumble pair of 100% merino long underwear has it allA versatile, lightweight merino-recycled polyester blend that offers superb breathability and wicking, making these a near ideal high performance bottom for any fast-paced adventureWarmer than most, lighter than the rest, this pair of long underwear re-defines what is possible from a synthetic base layerSlender and breathable, these are everything we expect out of a lightweight pair of long underwear
Rating Categories Carhartt Base Force... Ortovox 185 Rock'N'... Outdoor Research Al... Patagonia Capilene... REI Co-op Lightweig...
Warmth (30%)
6.0
8.0
6.0
7.0
5.0
Breathability (30%)
7.0
7.0
9.0
8.0
8.0
Comfort And Fit (30%)
5.0
8.0
7.0
7.0
6.0
Durability (10%)
7.0
7.0
7.0
5.0
6.0
Specs Carhartt Base Force... Ortovox 185 Rock'N'... Outdoor Research Al... Patagonia Capilene... REI Co-op Lightweig...
Material 100% Raised Mini-Grid Polyester 100% Merino wool 47% Merino wool / 47% Recycled polyester / 6% Spandex 100% Recycled polyester with HeiQ Fresh 92% Polyester / 8% Spandex
Fabric Weight N/A 185 g/m² 150 g/m² 147 g/m² N/A
Weight (size M) 5.2 oz 6.4 oz 6.8 oz 5.88 oz 5.46 oz
Insulation Weight Lightweight Midweight Lightweight Lightweight Lightweight
3/4 Boot-Cut Available? No Yes No No No
Fly? Yes No Yes Yes Yes
Dryer safe? Yes No No Yes Yes

Our Analysis and Test Results

Performance Comparison


For that time of the year when pure summer gives way to chilly...
For that time of the year when pure summer gives way to chilly mornings in the alpine, its best to bring along some lightweight warmth for your adventures.
Photo: Jill Rice

Warmth


Designed to be worn underneath work pants when the weather turns cold, the Carhartt Base Force Lightweight bottoms are built with a textured mini-grid polyester (think: gridded fleece) to eke out an extra bit of warmth by creating additional air space. They offer an extra boost of warmth over other lightweight models we tested and are indeed a great set of bottoms for laboring in. After an unseasonably cold front dumped snow about a month too early, these got us through the last of our farm work by providing just the right amount of warmth.

Sagging to show-off these bottoms... the Base Force Lightweight...
Sagging to show-off these bottoms... the Base Force Lightweight afforded just the right amount of warmth needed to get through a snowy morning of planting garlic.
Photo: Jill Rice

Insulated clothing works by holding body heat close to our skin, working to raise skin temperature and, ultimately, our core temperature. Although the Base Force Lightweight bottoms have the right idea at heart, the design concept is a bit flawed. The raised mini-grid polyester would work much better if it were on the inside of the pants, creating an insulating warm-air layer right next to your skin, instead of between the base layer and your pants (which are likely already exposed to the colder outside air at the ankle).

Opposite to the design of these R1 base layer pants, the...
Opposite to the design of these R1 base layer pants, the gridded-fleece of the Base Force Lightweight is on the outside, trapping a bit of heat but not nearly as effectively as if those grids were placed directly next-to-skin.
Photo: Jill Rice

Breathability


Looking at these from the inside, the design and construction are much like every other 100% polyester bottoms we have tested. The synthetic fabric is relatively thin, and an open weave allows for the easy escape of warm, moist air. The baggy fit, particularly around the ankles, does not particularly allow for moisture to be wicked away efficiently. But the "Force FastDry" does indeed dry very fast, even if these bottoms tend to accumulate sweat in places. We were perfectly comfortable wearing the Base Force Lightweight bottoms on an early morning getting out of camp but had to take them off once the sun got too strong.

These bottoms were great for backpacking when worn under a...
These bottoms were great for backpacking when worn under a lightweight rain pant, but less breathable than other models we tested when it came to more vigorous activities.
Photo: Jill Rice

Comfort and Fit


Much like a lightweight version of beloved gridded fleece for your bottom-half, the Base Force Lightweight pants are soft and comfortable to wear. The slightly baggy fit was a nice break from the norm, but we must warn you that these do tend to run a bit large, so you might want to consider sizing down. A size medium was a bit too baggy on the skinny mountaineer's frame of our 5'10", 155lb lead tester—Carhartt's model suggests that this size would fit much better on a similar frame standing at 6'2".

Our head tester is 5'10", 155lbs, wearing a size medium. We suggest...
Our head tester is 5'10", 155lbs, wearing a size medium. We suggest considering sizing down in these baggy bottoms to achieve a proper base-layer fit.
Photo: Jill Rice

Although we have no gripes in terms of comfort, the fit is a different story. These bottoms fit very well through the seat and upper thighs, but they flair to a baggy fit around the knees and particularly around the ankles. This can lead to uncomfortable bunching and often required constant adjustment to keep them in the right place. These issues are not helped at all by the sticky, gridded fleece that has a tendency to grab onto the inside of your outer-layer pant leg.

A close-up of the gridded face fabric (right) and the interior...
A close-up of the gridded face fabric (right) and the interior (left.) We believe these bottoms could be seriously improved by flipping this fabric to closer resemble the design of the eternal crowd-favorite R1 fleece.
Photo: Jill Rice

Durability


Gripes over the fit can be amended if you are able to try these pants on before purchasing, but underlying issues with durability are harder to foresee. On our first morning backpacking, before we really even had a chance to properly test the Base Force Lightweight bottoms, they managed to develop a tear where the mini-grid pant material meets the waistband. This was particularly surprising because we hadn't even left our tent. But to its credit, these pants hardly showed any signs of wear or tear after our overly-aggressive abrasion test — this is certainly a testament to a company known for designing hard scrabble workwear. Be mindful of possible snags and tears, but you likely don't have to worry about surface abrasion with these bottoms.

More likely a flaw in design than a lack of overall durability...
More likely a flaw in design than a lack of overall durability, these bottoms could see serious improvement in this category with sturdier seams.
Photo: Jill Rice

Value


For those looking to add just a touch of extra warmth to their layering system—especially for lower output activities and work-related wear—we consider the Base Force Lightweight bottoms an impressive option.

Taking advantage of the external gridded fleece by combining the...
Taking advantage of the external gridded fleece by combining the Base Force Lightweight bottom with an R1-style mid-layer. Now that's a warm sandwich!
Photo: Jill Rice

Conclusion


Offering a bit of extra warmth without the extra weight, the Carhartt Base Force Lightweight is a price-conscious option that backs up its affordability with remarkable performance. If the designers at Carhartt could solve some of the durability issues — by, for example, opting to incorporate stronger, flatlock seams — this pair of long underwear bottoms have the potential for significant improvement in rankings.

Warm and lightweight enough to perfectly fit our fall backpacing...
Warm and lightweight enough to perfectly fit our fall backpacing kit, these bottoms are sure to bring just the right amount of warmth to your next adventure.
Photo: Jill Rice

Aaron Rice

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